The present invention broadly relates to winding or unwinding apparatuses for the winding-up of substantially flat structures into a product coil or wound package and the winding-off of such flat structures from a product coil or wound package and, more specifically pertains to a new and improved construction of an apparatus for rotatably supporting or mounting a hollow, substantially cylindrical winding core or mandrel for rotation about the longitudinal axis thereof and for supporting on the outer or external side or surface thereof a product coil or wound package formed of flexible, substantially flat products, especially printed products. The present invention also relates to a winding core for employment with such an apparatus.
Generally speaking, the apparatus of the present invention comprises a support arrangement having at least one support element on which the winding core or mandrel can be brought to bear thereupon, and at least one pressing element which can be brought from an idle or ineffectual position into an operative or effectual position for pressing the winding core or mandrel against the at least one support element.
Such an apparatus is known, for example, from the European Patent Publication No. 0,161,569 and its cognate U.S. Pat. No. 4,601,436, granted July 22, 1986. The support arrangement of the apparatus known to the art comprises two support wheels, the axes of which are substantially parallel to one another. These two support wheels are rotatably and drivably mounted at a frame and form part of a friction wheel drive arrangement which further comprises an annular or ring-shaped friction wheel. This annular or ring-shaped friction wheel simultaneously constitutes the winding core upon which printed products are wound up conjointly with a winding strap. The exposed inner surface of the winding core comes into contact with the two support wheels and serves as a traction surface which is laterally delimited by inwardly projecting side flanges. The longitudinal axis of the winding core deposited upon the support wheels thus extends in a direction substantially parallel to the axis of rotation of the support wheels. A guide wheel is arranged beneath and in the center between the support wheels. This guide wheel can be brought from an idle position into an operative position, in which the guide wheel also bears against the exposed inner surface of the winding core, in order to press the winding core against the two support wheels. This known apparatus is associated with a relatively high constructional expenditure, considering the fact that both support wheels have to be driven and that a guide wheel must be provided to prevent slippage of the friction wheel drive arrangement.
In a winding core as known, for example, from European Patent Publication No. 0,236,561 and its cognate U.S. patent application Ser. No. 07/005,698, filed Jan. 22, 1987, the outer or external side thereof comprises a supporting surface for carrying a product coil or wound package formed of printed products. The printed products are wound up conjointly with a winding band or strap which at one end is fixedly attached to the winding core. The winding core comprises a groove for the winding band, such groove being open towards the outer or external side. On the inner or internal side of the winding core there are arranged two circumferential ribs which are located in planes extending in a direction substantially perpendicular to the longitudinal axis of the winding core, such planes extending beyond the center of gravity of the winding core. For rotatably supporting this winding core it is thus required that the winding core is either supported on both ribs or then only on one rib, whereby an axial support of the winding core is necessary if a tilting-off thereof is to be prevented.